For a pressure sensitive adhesive sheet, a release sheet is generally used which comprises a base material and a release agent layer formed on one surface of the base material (e.g., Patent Literature 1). Many of release sheets for a pressure sensitive adhesive sheet are usually used such that, after a pressure sensitive adhesive is coated and dried on a substrate which is being carried in a roll-to-roll manner, the release agent layer surface of the release sheet is attached to the surface of the obtained pressure sensitive adhesive layer. When a pressure sensitive adhesive sheet is produced in a roll-to-roll manner, the carrying speed from the roll may be constant, so that the release sheet is unlikely to be exposed to the air for a long time. As for the release sheet, in a pre-process of attaching the pressure sensitive adhesive layer of the pressure sensitive adhesive sheet and the release agent layer of the release sheet together, back-split processing (cut or half-cut) or the like may be performed for the release sheet.
When the processing as the above is performed, the release agent layer of the release sheet may be exposed to the air for a long time. If the release agent layer of the release sheet is exposed to the air for a long time in this way, there is a problem in that the peeling force of the release agent layer from the pressure sensitive adhesive layer becomes larger than that before the exposure to the air. In particular, as the peeling force increases such as in a sheet having tight releasability, the increase in the peeling force due to exposure to the air tends to be remarkable.
The increased peeling force of the release sheet as the above may cause release failure to occur when the release sheet is peeled off from the pressure sensitive adhesive sheet after the pressure sensitive adhesive layer of the pressure sensitive adhesive sheet and the release agent layer of the release sheet are attached together.